This Gangster Booster Pack was a Kickstarter Exclusive. It started with 4 new gangsters but added 4 more via stretch goal.
The Booster Pack contains 1 card with game variations and clarifications and the following new gangsters...
Goons : When hit by an action, ignore its effect (Once per game).
Highroller : Start each hand with 7 bids.
Hitman : +3 Infamy Points for each Gangster you have assassinated.
Identity Thief : Choose an opponent's Gangster. Identity Thief copies that ability for the rest of the game.
Rat : -2 Infamy Points (The player with the lowest Gangster bid takes the Rat).
Saboteur : Discard an opponent's 3, 4, or 5 bid played that turn (Once per game).
Spy : Pick an opponent. They must show you all of their action bids (Once per hand).
Swindler : When Laundering/Gambling look at an extra card and discard the one you don't want.
Each of these cards has a KS logo in the bottom right corner.